It's been three weeks since Japan's earthquake and tsunami started problems at a nuclear power plant. Since then, there have been a lot of alarming headlines about core meltdowns and radioactive contamination. But news reports are also suggesting that workers at the plant are getting control of the overheated reactors.

LINDA WERTHEIMER, host:

It is three weeks now since the Japanese earthquake and tsunami damaged the nuclear plant in Fukushima. Since then, there have been lots of alarming headlines about core meltdowns and radioactive contamination. But news reports also suggest that workers at the plant are getting control of the overheated reactors.

To help make sense of all this, we're talking to NPR science correspondent Jon Hamilton, who is monitoring the nuclear news from Tokyo.

Jon, what do we actually know about the situation at the plant? Are things as bad as they were a couple of weeks ago?

JON HAMILTON: It doesn't look like they are. What facts have come out are, you could say, actually a little bit reassuring. So you remember those explosions and the fires and stuff, all that happened in the first three or four days after the earthquake. So that was, whatever, March 11th through March 15th. Since then there's actually been some pretty good news. For example, the pressure and the temperature in the cores of the reactors seems to be pretty stable. No one seems to be worried about the spent fuel storage tanks anymore. They've restored electrical power to much of the plant. And with every passing day here, the reactor cores are producing less heat. That's because the leftover radioactive materials are decaying.

All that said, not everything is great. There is a lot of water that was apparently used to cool the reactors that appears to be getting into the ocean. And that's bad. Fortunately, a lot of it seems to be in the form of this radioactive iodine, and that disappears quickly from the environment.

WERTHEIMER: How open do you think TEPCO, the company that owns this plant, how open have they been about what they're doing and things are going? I guess what I'm asking is, can you trust this information?

HAMILTON: Open and TEPCO are not words you usually hear in the same sentence. The Tokyo Electric Power Company is very guarded, and in fact the president of the company has been criticized a lot for essentially not appearing in front of TV cameras or answering questions at all.

And you know, one of the reasons they may be so hesitant is that the company has not looked great, and they certainly have made some big mistakes. At the beginning there was a lot of talk that they should have started pumping seawater into the reactors sooner. And just today they had to put out a statement sort of admitting they had made a big mistake in measuring radioactive material in underground water. They said they just got it wrong.

WERTHEIMER: So what about the Japanese government? How are they doing?

HAMILTON: I think they'd be rated as having done a lot better. The Nuclear Safety Agency has been having a press conference every day. The prime minister's office also holds at least one press conference a day, and they've also provided a lot of the analysis about what's going on inside the plant. So I think their grade would definitely be a bit better than TEPCO's.

WERTHEIMER: What about foreign experts? I understand there are some people who've come in to help out. Are they talking about what's going on?

HAMILTON: There are definitely foreign experts here. More recently, France, of course, has sent some people. The U.S. has been supplying cooling water and also some expertise.

Recently, Robert Gale, a U.S. doctor who actually was involved in treating people in Chernobyl, was visiting, and he's one of the few who actually made a public statement, perhaps because he's not here officially on behalf of a government. He said he seemed pretty positive about how Japan is handling the situation.

The other experts have been extremely cautious. You know, they are here as guests of the Japanese government and they tend to leave the statements to others.

WERTHEIMER: So Jon, why is it that if you keep up with the news on this reactor, it seems like one day things are better and the next day there's some kind of terrible news, imminent catastrophe - why is that happening? Is it a media problem?

HAMILTON: Well, certainly you get a different tone depending on which media outlets you look at. Interestingly enough, in Japan the headlines tend to be a bit less alarming than in some of the U.S. papers I've read. But I think part of the thing is that every little thing that happens here is being reported, and a lot of the little things sound scary, all these little details.

You know, if you imagine if you had a doctor giving you reports of every tiny thing that happened to a patient in the intensive care unit, it would be, well, one day their body temperature's up a little bit, their kidney function is off a little bit. Individually those things sound scary and you might lose track of the fact of what they're really telling you that the patient is getting better.

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